Beaming multiple voices in lilypond

Question

I have the following in lilypond:

\version "2.23"

\header {
  title = "Example"
}


global = {
  \key c \major
  \numericTimeSignature \time 4/4
  \tempo 4 = 104
}

rh = {
  \clef "treble"
  \relative c' {

    <f bes>8 g8
    <<
     { ees8 bes8~ bes8 }
     \\
     { ees4~ \stemUp ees8 }
    >>
    ees8 f4~ | <g f>2. r8

    
  }
}

song = {
    \new PianoStaff \with { instrumentName = "Piano" } <<
      \new Staff = "treble" \rh
     >>
}

\score {
  \song
  \layout { }
}

\score {
  \song
   \midi { }
}

which produces a bit of a mess (see below). I'm new in lilypond to working with multiple voices. How would I beam the 3 single stems of the 8th notes together? And raise the tie of the Eb so that it doesn't run through the lower notes?

Answer 1

I think what you want is something like this:

...
\relative c' {
    <f bes>8 g8
    <<
        { ees4~ ees8[ ees8] }
        \\
        { ees8 bes8~ bes8[ ees8] }
    >>
    f4~ | 
    <g f>2. r8   
}
...

Notes:

• I have swapped the upper and lower voices around, so that the stems go in the right direction automatically.
• Beams that don't appear automatically can be forced with [ and ]. However you can't join beams across voices (at least not easily).
• You can change the side that a tie (or slur) is on by placing a ^ or _ before it, but I didn't end up needing this.